The spoiled-brat Princeton grad accused of killing his millionaire father because the older man cut his monthly allowance by $200 whined to a Manhattan judge Wednesday that he’s being poisoned by radioactive fallout from batteries at Rikers Island.

Thirty-one-year-old failed stockbroker Thomas Gilbert Jr. told Judge Melissa Jackson that he had expressed his qualms to the medical staff there to no avail.

Gilbert also complained about how his jailhouse cell lacks cable TV. He made multiple calls to the president of Cablevision seeking help, sources said.

Gilbert allegedly murdered his father, Thomas Gilbert Sr., after the hedge-fund founder slashed his $2,400 monthly allowance to $2,200 in January 2015.